Lecture 7 (endocrine system) Flashcards

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1
Q

Hormones? (in general)

A

Most hormones are chemicals secreted by a group of cells in one part of the body and carried through the bloodstream to other parts of the body, where they act on specific target tissues to produce specific physiological effects.

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2
Q

What does it mean that hormones act gradually?

A

Activating behavioral and physiological responses hours or weeks after entering the bloodstream. The changes may persist for days, weeks, or years.

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3
Q

Do hormones act as a switch?

A

No, they tend to act by changing the intensity or probability of evoked behavior, rather than as a switch.

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4
Q

What can hormones affect?

A

Hormones can affect only those cells that possess corresponding receptor proteins to recognize the hormones and alter cell function.

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5
Q

What are the three ways in which hormones are regulated?

A

Autocrine feedback, target cell feedback, and brain regulation.

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6
Q

Autocrine feedback?

A

is regulated by negative feedback.

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7
Q

Target cell feedback?

A

example: insulin and glucose. It is a biological response which gives feedback to the endocrine cell if it has to secrete more or less hormone.

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8
Q

Brain regulation?

A

a biological response. But the difference is that it will lead back to the brain so it can decide if it needs to secrete more or less hormone.

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9
Q

How is the endocrine system regulated by hypothalamus?

A
  • Directly: neuroendocrine products from hypothalamus by the posterior pituitary gland.
  • Indirectly: through releasing hormones which regulates the anterior pituitary gland.
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10
Q

What is hypothalamus itself regulated by?

A

by synaptic inputs from other brain parts and the body. Isn’t covered by the blood-brain-barrier.

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11
Q

How is the endocrine system regulated by pituitary?

A

Regulates hormone secretion from other endocrine glands.

  • The posterior part doesn’t produce hormones. The hormones are transported via axons in the neurosecretory cells.

*The anterior part is regulated by releasing hormones from the hypothalamus. It secretes tropical hormones which regulates other hormones.

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12
Q

Posterior pituitary and hormone secretion?

A

o Oxytocin: stimulates contraction of uterine muscles; stimulates release of milk by mammary glands.

o Vasopressin (AVP), or antidiuretic hormone (ADH): stimulates increased water reabsorption by kidneys; stimulates constriction of blood vessels.

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13
Q

Anterior pituitary and hormone secretion?

A

o Growth hormone (GH): stimulates growth

o Thyroid-stimulating hormone (TSH): stimulates the thyroid

o Adrenocorticotropic hormone (ACTH): stimulates the adrenal cortex

o Follicle-stimulating hormone (FSH): stimulates growth of ovarian follicles and of seminiferous tubules of the testes.

o Luteinizing hormone (LH): stimulates conversion of follicles into corpora lutea; stimulates secretion of sex hormones by gonads.

o Prolactin: stimulates milk production by mammary glands.

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14
Q

Hypothalamus and hormone secretion?

A

Oxytocin; vasopressin.

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15
Q

Pineal and hormone secretion?

A

Melatonin: regulates seasonal changes; regulates puberty.

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16
Q

Adrenal cortex and hormone secretion?

A

o Glucocorticoids: inhibit incorporation of amino acids into protein in muscle; stimulate formation and storage of glycogen; help maintain normal blood sugar level. For example, cortisol.

o Mineralocorticoids: regulate metabolism of sodium and potassium. Works on the kidney. Is regulated by the kidney hormone renin and not by pituitary.

o Sex hormones: regulate facial and body hair.

17
Q

Adrenal medulla (binyremarven) and hormone secretion?

A

o Catecholamines: prepare body for action.
o Fight or flight response.
* Epinephrine and norepinephrine

18
Q

Gonads (testes) and hormone secretion?

A

Androgens: stimulate development and maintenance of male primary and secondary sexual characteristics and behavior.

19
Q

Gonads (ovaries) and hormone secretion?

A

o Estrogens: stimulate development and maintenance of female secondary sexual characteristics and behavior.
o Progestins: stimulate female secondary sexual characteristics and behavior; main pregnancy.

20
Q

Thyroid and hormone secretion?

A

o Thyroxine: stimulate oxidative metabolism.
o Missing of the thyroid hormone can lead to kretinisme: reduced growth.
o Calcitonin: prevents excessive rise in blood calcium.

21
Q

Pancreas and hormone secretion?

A

o Insulin: stimulates glycogen formation and storage.
o Glucagon: stimulates conversion of glycogen into glucose.

22
Q

CRH (corticotropin releasing hormone) and its function

A

affects adrenocorticotropic hormone (ACTH) which affects the adrenal cortex.

23
Q

TRH (thyrotropin releasing hormone) and its function

A

affects thyroid-stimulating hormone which affects thyroid.

24
Q

GnRH (gonadotropin releasing hormone) and GnIH (gonadotropin inhibiting hormone) and their functions

A

affects the gonads.

25
Q

Prolactin releasing peptide and prolactin inhibiting factor and their functions

A

affects prolactin and the mammary glands.

26
Q

Which hormones affect the bones?

A

Somatocrinin (stimulates) and somatostatin (inhibits)

27
Q

Psychosocial dwarfism?

A

Inhibited growth caused by psychosocial stress or neglect. Growth is regulated by the growth hormone, cortisol and somatomedins.

28
Q

Psychosocial stress can lead to reduction in which hormone?

A

reduction in the releasing hormone somatocrinin –> reduced growth hormone.

29
Q

Hyperthyroidism?

A

Looks like anxiety

30
Q

Hypothyroidism?

A

Looks like depression and can result in a real depression.

31
Q

How does endocrine communication?

A

The chemical signal is a hormone released into the bloodstream to selectively affect distant target organs.

32
Q

Neuroendocrine cells?

A

A lot like neurons, but they do not release a neurotransmitter into a synapse at their end of the axon, they release hormone into the bloodstream.

33
Q

Neuromodulators?

A

a blend of neurotransmitter and hormone.

34
Q

Peptide hormone?

A

Composed of a string of amino acids.

35
Q

Amine hormones?

A

smaller and simpler, consisting of a modified version of a single amino acid.

36
Q

Steroid hormones?

A

derivatives of cholesterol, sharing its structure of fours rings of carbon atoms. Can easily pass through membranes.

37
Q

The effects of hormones on cells?

A

Hormones exert far-reaching effects by (1) promoting the proliferation, growth, and differentiation of cells and (2) modulating cell activity.